1. Field of the Invention
The present invention relates to transport arrangements for photosensitive material in a processor, and specifically to an arrangement to eliminate excessive tension on the photosensitive material during movement thereof through a processor.
2. Description of the Prior Art
The processing of photosensitive materials typically requires that the materials be saturated with various development chemicals. Once a sheet of photosensitive material has been exposed to such chemicals, it then must be dried for use in creating prints and copies of the image borne thereon.
Photosensitive material processors have been developed which feed a sheet of photosensitive material through the necessary chemicals in an orderly fashion and then dry the sheet for further use. Typically, this sheet is driven by engagement with various rollers or matched roller pairs to follow a desired processing path. Each sheet of photosensitive material will bear one or more unique photographic images, which are often incapable of being reproduced in exactly the same form. Thus, great care must be used in handling such sheets.
In many cases, the sheet of photosensitive material is in the form of a roll or long sheet which must be processed. As fed through the processor, therefore, portions of the sheet may be in contact with all of the rollers along the processing path at the same time. The path is typically serpentine in nature, so that the sheet can be dipped into tanks of the various processing chemicals as it passes along the processing path. Because of the bends in the path, excessive tension is at times placed on the processing material as it travels from roller to roller.
In some processors, the processing fluid tanks are removable and not securely fastened to the processor. The tension placed on the processing material can not only damage the material, but also cause the pulling together of rollers and processing tanks which can cause the tanks to dump over. Neither of these results is desirable because of the great potential for damage to the unique photographic images borne by the photosensitive material.
Potential solutions to this problem include slower transport times for the processing material through the processor to thereby reduce the amount of tension placed on the material. In addition, slippery or low-friction rollers have been used in an attempt to reduce the tension placed on the photosensitive material by allowing the material to slip over those rollers, even though those rollers are driven to drive the paper along the processing path. These solutions proved inadequate. Slower running times reduces the productivity of a film processor and allowing the processing material to slip over rollers increases the chance for scratching and damage to the material as it is processed. A photosensitive material processing drive arrangement is thus needed which will maintain the material in tension as it passes through the processor to eliminate excessive looping, but which does not place excessive tension on the material to cause damage thereto or tipping of the processing fluid tanks in the processor.